"We have agreed with the prime minister to cease all acts of violence against Israelis and against Palestinians wherever they are," Abbas said at the summit on Tuesday at the Egyptian resort of Sharm al-Shaikh.
Sharon said the Palestinians had agreed to end anti-Israeli actions and that in parallel "Israel will cease its military operations against the Palestinians in all areas".
"We have an opportunity to turn our back on the bloody path imposed on us over the last four years," Sharon said, adding he was hopeful that the summit would mark the day when the peace process was re-launched.
The summit, the first between Israeli and Palestinian leaders in over four years, comes amid a growing rapprochement after Abbas' election a month ago and a new commitment by the United States to seek Middle East peace.
"The calm that is currently prevailing in our territories signals the start of a new era, the start of a hopeful peace," Abbas said.
Abbas (L) with Sharon, Mubarak
and Jordan's King Abd Allah (R)
"What we have announced today is the implementation of the first phase of the road map ... and an essential step to give us a chance to put the peace process back on track."
Egyptian President Husni Mubarak hailed what he said was a "positive spirit" between the Israelis and Palestinians, and said he hoped it would lead to an "honest and serious" implementation of the road map peace plan.
Sharon also confirmed that Israel would release hundreds of Palestinian prisoners.
The summit comes just a day after new US Secretary of State Condoleezza Rice wrapped up a visit to the region, declaring that both Sharon and Abbas had accepted invitations to meet US President George Bush at the White House.
"What we have announced today is
of the first phase
of the road map"
The two sides have not yet patched up some of their thorniest differences, such as Israel's controversial West Bank separation wall, Israeli settlement activity and the closure of Palestinian groups in East Jerusalem.
"The discussions [on all these matters] will take place during the summit and afterwards," Palestinian Negotiations Minister Saib Uraiqat said.
Another burning issue is the fate of 8000 Palestinian prisoners held behind bars in Israel.
Israel said last week it would free 900 prisoners, with a first batch of 500 set to be freed soon after the summit.
Aljazeera correspondent in Gaza Wail al-Dahduh reported that people reacted in varied ways to the ceasefire announcement.
The summit has raised people's
hopes in spite of past failures
Some were optimistic, some pessimistic and others were unconcerned about the summit, as Gazans have had a long and bitter experience with such gatherings.
However, all citizens were hopeful about the outcome, al-Dahduh said.
Aljazeera's correspondent in Ram Allah, Shireen Abu Aqla, reported that Palestinians, while hoping for peace, were mostly concerned about the issue of prisoner release.